Safety switch



Aug. 12 1924.

C. D. PLATT SAFETY SWITCH Filed Deo. 18, 1922 2 Sheats-Sheet l 7 INVENTOR 2 6.9.5 BY.

TOR NE Y Aug. 12 1924.

C. D. FLATT SAFETY SWITCH 2 Sheets-Sheet 2 Filed Dec. 18 1922 INVENTOR er: 'IIIIIIIIIIII 'Patented Aug. 12, 1924.

UNITED STATES CLARENCE D. PLATT, OF BRIDGEPORT, CONNECTICUT.

SAFETY Application led December To all lwhom it may concern:

Be it known that I, CLARENCE D. PLATT, a citizen of the United States of America, and residing at Bridgeport, in the county of F airfield and State of Connecticut, Ahave invented new and useful Improvements in Safety Switches. of which the following is a specification.

This invention relates to safety switches of the type having a switch and fuses to protect the load circuit enclosed within a casing and a cover having a sliding panel to give access to the fuses when the cover is closed.

An object of the invention is to provide in a switch of this type a simple, rugged construction which prevents opening of the panel when the switch contacts are closed and closing of the contacts when the panel is open.

A further object is to provide such a switch having a minimum number of parts, with consequent ease of assembly and cheapness of manufacture.

Fig. 1 is an end view partly in section showing the contacts open, the casing being sectioned along the line 1-1 of Fig. 4.

Fig. 2 is a front elevation of the switch casing with the cover closed, the switch mechanism being indicated in dotted lines with the contacts closed.

Fig..3 is a longitudinal section taken on theline 3-3 of Fig. 2 showing the contacts and panel closed.

Fig. 4 is a view similar to Fig. 3 but showing the contacts and panel open, part of the base being in elevation.

Fig. 5 1s a perspective view of the movable contacts Iand the plate which connects them to the operating bar, and

Fig. 6 is aperspective view of a hasp to lock the casing. I

The invention is illustrated in connection with a double pole switch, having a box or casing 7 and a cover'8-preferably hinged to one of the side walls=of the casing. Secured to the back wall ofthe casing is an insulating base 9 having two fuse sockets 10 at its lower end, and a projection 11 extending nearly to the cover. Posts 12 fixed to the basel pivotally support the movable contacts-or blades 13 which cooperate with the fixed spring contacts 14. The incoming line conductors maybe connected to the fixed contacts asby binding screws 15, while binding screws 34 connected to the fuse SWITCH.

18, 1922. Serial No. 807,524.

edge of plate 17, which thus serves to interconnect the blades and operator.

To give access to the fuses the cover is apertured near its lower end, and a -panel 21 is provided normally to close this aper ture, guide rails 22 being secured to the opposite side walls of the cover to support the panel close to the inner surface of the cover and slidable relative thereto. A but'- ton 23 secured near the front edge of the cover facilitates its operation and limits its movement by abutting against the edges of the aperture.

In order that the panel may be opened only when the contacts are open, I provide on plate 17 an arm 24 eXtendin when the contacts are closed into the pat of movement of the panel and close to the rear edge thereof (Fig. 3). The end of arm 24 thus acts as a stop to prevent appreciable opening movement of the panel when the contacts are closed. When the contacts are open (Fig. 4) arm 24 is withdrawn from the path of movement of the panel into a slot 25 in the projection-11, so as to permit free movement of the panel.

To prevent closing of the contacts when the panel is open, I carry the outer curved edge 26 of arm 24 beyond the plane of the panel and the fiat portion of the cover, and arch the cover at 27 to afford clearance for the plate when the panel is shut (Fig. 3). When the contacts and the panel arevopen, the panel stands in the path of the plate and thus prevents closing movement of the contacts. An attempt to close the contacts when the panel is open would tend to force the cover outwardly and Vmight result in forcing it opensuilciently to permit such closing movement. I therefore bend over one edge of plate 17 to form a marginal flange 28 which lies parallel and close to the lower surface 'of panel 21 when the contacts are open, and interlocks with a hook member such as the bar 29 secured longitudinally on the inner surface of the panel when the contacts are open (Figs. 1 and 4). Obviously this construction permits free movement of the panel so long as the contacts are wide open, but until the panel is tight shut any closing movement of the contacts will merely bring the leading edge of the flange 28 into engagement with the hook member 29, and by inward pressure on the latter will counteract any tendency to force the cover open as above described.

When the switch and the sliding panel are both in the open position as shown in Fig. d, the flange 28 on member 17 overstands or interloclrs with the hoolr member 29 on the panel and thus prevents the opening of the box cover while the parts are in this posi' tion.

l also provide a simple yet effective locking device consisting of a hasp 30 and an angular lug 3l secured to the end wall of the casingand the side flange of the cover respectively. rlhe hasp consists of a strip of sheet metal punched at one end .to accommodate a rivet 32 by which it is pivoted to the casing, and slotted asat 33 to fit over lug 3l which may be punched to receive a padlock.

TWhile I have described my invention in connection with a switch havingl two sets of contacts of the positive make and break type, obviously it is equally applicable to switches with a different number of contacts and of other types. Moreover parts may be substituted for other parts, changed in shape, added or dispensed with entirely, all without departing from the spirit of my invention.

l claim:

l. In a safety switch, a casing, a cover having a panel slidable to open or close an aperture therein, a fixed contact, a movable contact, an operating bar, and a member to interconnect the movable contact Vand bar and to prevent opening of the panel when the contacts are closed.

2. In a safety switch, a casing, a cover having a panel slidable to open or close an aperture therein, a fixed contact, a movable contact, an operating bar, and a member to interconnect the movable contact and bar and prevent closing of the contacts when the panel is open.

3. In a safety switch, a casing, a cover therefor and having an aperture therein, a sliding panel to close said aperture, fixed switch contacts, movable switch contacts, a cross-bar connecting said movable contacts, a switch operating crank, an arcuate plate secured to said cross-bai' and having operable connection with said crank, a flange on said panel and a flange on said arcuate plate member to engage the flange on said paneL and prevent closing of thev switch when the panel is in open position.

4. In a safety switch, a casing, a cover therefor having an opening, a slide for closing said opening, fuse sockets in one end Leontine of the casing in line with said opening, staticnary and movable contacts in the other end of the casing, an operating bar, a plate carried by said movable contact and connected to said operating bar, said plate having a portion obstructing the movement of said slide when the switch is closed and another portion obstructing the movement of the movable switch contact when the slide is open.

5. ln a safety switch, a casing, a cover having a sliding panel to open or close an aperture therein, a pair of fixed contacts, a pair of movable contacts, an insulating cross bar connecting said movable contacts, a contact operator, and a plate secured to the cross bar and in engagement with the operator, said plate having an arm extending when the contacts are closed into the path of movement of the panel and near the rear edge thereof to prevent opening of the panel.

6., llii a safety switch, a casing, a cover having a sliding panel to open or close an aperture therein, a pair of fixed contacts, a pair of movable contacts, an insulating cross bar connecting said movable contacts, a contact operator, and a plate secured to the cross bar and .in engagement with the operator, said panel when open-serving as an abutment for one edge of said plate to prevent closing of the contacts.

7. l'n a safety switch, a casing, a cover having a sliding panel to open or close an aperture therein, a pair of fixed contacts, a pair of movable contacts, an insulating cross bar connecting said movable contacts, a plate secured to said cross bar, a contact operator, a hook member secured to the inner face of the panel and a marginal flanfe on said plate adapted to interlock with said hook member when'the panel is open to prevent closing of the contacts.

8. ln a safety switch, a casing, a hinged cover therefor having an opening, a slide for closing said opening, fuse sockets in said casing in line with said opening, stationary and movable switch contacts in said casing, a plate connected to said movable switch contact having a portion preventing the opening movement of said slide when the switch is closed and having another portion preventing the closing of the switch when the slide is open and having another portion preventing the opening of the hinged cover when the slide is open and the.

switch is open.

9. in a safety switch, a casing, a xed contact, a movable contact, an operat ing bar mounted for rotation on an axis transverse to the casing, a plate to interconnect the movable contact and operating bar, a cover ,for the casing having a flat body portion and an outardly arched transverse portion, a panel slidable in the cover, and .an arm on the plate extending beyond the plane of the lat yportion of the cover into the path of movement of the panel and near the rear edge thereof when the contacts are closed to prevent opening of the panel, said plate lying entirely below said panel when. the contacts are open to permit opening of the panel, and said panel when open lying in the path of movement of said plate to prevent closing movement of the contacts.

10. In a safety switch, a casing having walls, an insulating base secured to the rear wall of the casing and having an outwardly extending transverse projection, said base having provision ior fuse sockets at one side of the projection, a number of fixed contacts secured to the base on the other side of the projection, a number of pivotally mounted blades to cooperate with said contacts, a. casing cover having asliding panel, a plate movable With the blades and having an arm extending into the path of movement of the panel when the contacts are closed, said projection having a slot to accommodate said plate arm, and means for moving the blades to open position and moving the plate arm into the slot and out of the path of movement of the panel to permit opening of the panel.

CLARENCE D. PLA'IT. 

